Seeing all three readings during cycling

Question
I have a 55 gallon that has been up and running for 3 weeks.  I have five 1.5" Long Fin Red Minor Tetra that are doing well. My temp is steady around 78 degrees and I have not vacuumed due to trying to cycle the tank. I was getting no readings for ammonia, nitrite or nitrate until last week when I started seeing nitrite (but no ammonia, which to me was odd).  I added a bit of gravel from my Betta's 5 gallon cycled tank last Wednesday and I am now seeing low levels of ammonia (.25), nitrite (.25) AND nitrate (5.0).  Is this normal?  When ammonia or nitrite started to get to the stress level last week (between .25 and .50), I would do about a 20% water change to help bring it back down.  When people say ammonia and nitrite should "spike" does that mean really climb high or is a small raise in these levels adequate to help the cycling continue?  I'm getting a bit confused with all I read about cycling.  I don't want to stress my fish out too much during this whole process.  Thanks for your help!

Answer
Hi Bill:  Tank cycling can be very confusing... this is the deal... gravel vacuum and do a a 10-20% water change at the same time... Do not worry too much about the tank cycle...its going to cycle regardless...and its cycle process should include tank maintenance such as gravel vacuuming... I know this is going to sound odd... but the tank will get use to your tank maintenance schedule and if you are consistent with what you do the cycle process of the tank will mostly adjust to a routine of a weekly loss of water of up to 20%.... I honestly try not to change more then 15% of my water but I am religious about cleaning my gravel....Hope this helps... dave